Refrigerating apparatus



Sept. 1, 1936. D. H. REEVES 2,052,894

' REFRIGERATING APPARATUS Original Filed April 16, 1930 2 Sheets-Sheet lW W 141E032? Sept. 1, 1936. D H V 2,052,894

REFR IGERAT ING APPARATUS Original Filed April 16, 1930 2 Sheets-Sheet 2IN VENT OR Patented Sept. 1, 1936 UNITED STATES REFRIGERATING APPARATUSDonald H. Reeves, Dayton, Ohio, assignor, by Y mesne assignments, toGeneral Motors Corporation, a corporation of Delaware Application April16, 1990, Serial No. 444,639 Renewed May 13, 1935 9 Claims. (01. 236-92)This invention relates to refrigerating apparatus and more particularlyto the control of such apparatus. v

An object of this invention is to provide an improved refrigeratingsystem in which the cooling I action of the evaporator is controlled byvariation in pressure in a fluid container, and to provide for varyingthe pressure range of the fluid in the container.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings, wherein a preferred form of the present invention is clearlyshown.

In the drawings:

Fig. 1 is a view in cross section of a portion of a refrigeratingapparatus and showing features embodying the invention. 1 a

Fig. 2 is a longitudinal sectional view of the expansion valve andcompensating device forming a part of the invention; and

Fig. 3 is a diagrammatic view of the refrigeratins system.

Referring to the drawings, there is shown a cabinet comprising a coolingcompartment 2| and a machine compartment 22. The cabinet is arranged forhousing a refrigerating apparatus in the compartments 2| and 22. Thesecompartments are separated by a wall 21. A cool- .ing unit is carried byand'below the wall 21 and extends within the cooling compartment, and acompressor 32, driving motor 33 and condenser 35 are carried by -or ontop of said wall.

Referring more in detail to the drawings and particularly to Fig. 3, therefrigerating apparatus 25 comprises the refrigerating element orcooling unit 30 having an outer coiled pipe 31 for cooling thecompartment 2| and having an inner coiled pipe 38 in thermal contactwith a freezing compartment 40 adapted to receive a plurality'oficemaking receptacles 4|. The cooling unit is supplied withliquld'refrigerant under the control of an expansion valve from areceiver 41. Refrigerant evaporated in the cooling unit is withdrawn bythe compressor 32 actuated by the threaded in a yoke Bl surrounding theinlet and supported on a flexible metal diaphragm which forms one wallof the chamber 5|, being clamped between the casing 5|! and end plate 62by bolts 64. A removable plug- 65 affords access to the chamber 5| foradjusting the valve. The end plate 62 provides a chamber 61 on the backside of the diaphragm 60. The diaphragm 60 is acted upon by the force ofthe pressure in the chamber 61 which tends to open the valve and theforce of the pressure of the refrigerant-in the valve chamber whichtends to close the valve. Whenever the compressor is running it reducesthe pressure in the valve chamber and permits the valve to open. The re-5 frigerant expanding upon entering the valve chamber tends to increasethe pressure and consequently tends .to close the valve. Thus, when thepressure in the chamber attains a certainlow value, the valve will bemoved from its seat to 20 admit more refrigerant to the chamber 5| andlikewise to the evaporator 30. Conversely, when the pressure in thechamber 5| attains a certain high value, the valve will close to shutoff the flow of refrigerant to the evaporator. Thus it is 25 apparentthat, during the operation of the system, valve 45 normally tends tomaintain a constant pressure within the evaporator 30.

It is desirable to maintain the back side of the diaphragm covered atall times to prevent moist 30 air from circulating or entering thechamber ill on the back side of said diaphragm. If air were permitted tocirculate inback of the diaphragm, frost would collect thereon and thisfrost would materially affect the operation of the valve. Merely sealingthe back of the diaphragm will not entirely remove defects, due tochanges in operation of the valve, because the air in back of thediaphragm will be chilled and, due to the back side being sealed, thepressure on the back side will decrease. Hence under certain conditions,

- for example, at the start of the refrigerating cycle, when the valveis relatively warm, relatively high pressure is present in back of thediaphragm, and, after the refrigerating cycle has continued for awhile,the valve will be colder and a lower pressure is present back of thediaphragm. These changes in pressure often cause a decrease inefflciency of operation.

In order to cause the valve 55 to function more correctly under varyingconditions, a compensating or governing device has been provided forcontrolling the pressure in the back of the diaphragm. This device isherein shown as comprising an 7 adjustable fluid container comprising atube 16 55 and a bulb 15 in the form of a sylphon or bellows. The bulbI5 is sealed to the back side of the diaphragm by the tube 16 andconnection IT. This bulb is disposed outside of the zone of directcoolinginfluence of the evaporator and is herein shown located withinthe machine compartment 22 and held in place by a bracket 80. By usingthe bulb, not only the air in the back of the diaphragm, but also theair in the bulb and tube 16 must be chilled before the pressure on theback side of the diaphragm will be decreased. And, it is readilyapparent that any desired pressure may be obtained in back of thediaphragm. For example, the bulb may be placed in such location withinthe machine compartment so that the temperature of the fluid within thebulb will be increased artificially. The bulb may be filled with anysuitable fluid, and for instance at atmospheric pressure, andpreferably, for practical purposes, it has been found desirable tomaintain air in the bulb and to carry. saidbulb as shown, in which thebulb is subjected to environment temperatures within the machinecompartment 22, which temperature will be ordinarily a little higherthan room temperature.

It is desirable to vary the pressure in the fluid container in order tocontrol. the pressure at which the valve opens and it may be desirableto change this adjustment to suit certain operating conditions. Thus, inthe event it is desired to vary the pressure on the back side of thediaphragm in order to vary the pressure in the evaporator 30, I haveprovided means for expanding or contracting the adjustable fluidcontaining bulb 15. This means may comprise a screw 90 threaded into aninwardly directed boss 92 formed on a sealing ring 93 which forms oneend of the bulb-l5. By this arrangement the screw 90 normally maintainsthe expansible bulb 15 in a fixed position, and by a movement of screw90 the bulb may be expanded or contracted. Thus by turning the screw 90,the adjustable fluid containing bulb may be compressed or expanded tochange the pressure of the air in said bulb, tube 16 and chamber 61 toeither super-atmospheric or sub-atmospheric pressure as desired. Thisarrangement is meritorious in that the pressure on the back side of thediaphragm may be varied without unsealing the bulb or its connection tothe back side of the diaphragm. Thus, it is possible to adjust thecompensatingdevice to vary the pressure on the back side of thediaphragm without the possibility of air circulating about the back sideof the diaphragm when the temperature of the diaphragm is such thatmoisture would collect on the backside thereof. Thus the bulb, tube 16and chamber 51 may be filled with air, sealed and adjustments made tovary the pressure on the back side of the diaphragm without affectingthe emciency of the valve. Also, this arrangement is advantageous sincethe bulb may be disposed in a ready accessible place so that adjustmentsthereof may be easily made.

From the foregoing it can be seen that the refrigerating system willoperate at a higher. back pressure in warm weather or in a warm roomthan in relatively cold weather or room, because a higher pressure willbe maintained in back of the diaphragm in the warm environment. Thisfeature of the invention is meritorious in that a relatively high backpressure is desirable in warm weather and -a lower back pressure isdesirable in colder weather; since, as well understood, higherefficiency is attainable with a relatively high back pressure and muchhigher efliciency is most desirable in warmer temperatures because ofgreater heat leakage through the cabinet walls. If a refrigeratingapparatus is operated at a relatively high back pressure in colderweather, the temperature of the cooling unit is reduced quickly becausethe heat leakage through the cabinet is relatively small. Therefore, theperiod for freezing is relatively small. Moreover, the refrigeratingphases do not take place as frequently in cold weather as in warmweather because there is less heat leakage through the cabinet,consequently the water in the receptacles ll will not be frozen asquickly in colder weather. Therefore, it is desirable to prolong therefrigerating phase in colder weather and this can be accomplished byreducing the back pressure in the system. The governing device hereinshown regulates the back pressure automatically to produce the desiredresults, because, as the environment temperature falls, the pressurewithin the bulb 15 decreases and less force is applied to the back sideof the diaphragm. Therefore, a lower pressure must be produced in theevaporator and in the expansion valve 45 before the valve 55 opens.

Thus it is apparent that the governing device herein shown causes thesystem to function properly under different climatical conditions, inthat the valve and bulb may beadiusted to automatically maintain thedesired back pressure for efficient operation in warm weather andprovides for quickly freezing or congealing substances in colderweather. Thus the refrigerator will operate efflciently irrespective ofthe climatical conditions.

While the form of embodiment of the invention as herein disclosed,constitutes a preferred form, it is to be understood that other formsmight be adopted, all coming within the scope of the claims whichfollow.

What is claimed is as follows:

1. A refrigerant expansion valve including a valve chamber having aninlet and an outlet, a valve for controlling the flow of refrigerantthrough the valve chamber, a diaphragm connected to operate said valve,9. fluid chamber on one side of said diaphragm, a thermostatic bulbconnected to said fluid chamber, said fluid chamber and said bulbcontaining a gas non-condensible at operating temperatures and means forvarying the pressure in said fluid chamber.

2. A refrigerant expansion valve including a .valve chamber having aninlet and an outlet, a

valve for controlling the flow of refrigerant through the valve chamber,a diaphragm connected to operate said valve, 9. fluid chamber on oneside of said diaphragm, a thermostatic bulb connected to said fluidchamber, said fluid chamber and said bulb containing a gasnon-condensible at operating temperatures and means for varying thevolume of said thermostatic bulb.

3. A refrigerant expansion valve including a valve chamber having aninlet and an outlet, a valve for controlling the flow of refrigerantthrough the valve chamber, a diaphragm means subject to refrigerantpressures within said valve chamber for operating said valve responsiveto said pressures, and fluid pressure means containing a gas which doesnot change its state at operating temperatures for loading saiddiaphragm means and for regulating the movement thereof, said fluidpressure means including means for adjusting the pressures within saidvalve chamber having an inlet and an outlet,

statically regulating the loading of said diaphragm by fluid pressures,said fluid pressure means including means for varying the volume thereoffor adjusting the fluid pressures therein.

5. A refrigerant expansion valve including a valve chamber having aninlet and an outlet, avalve for controlling the flow of refrigerantthrough the valve chamber, a diaphragm means subject to refrigerantpressures within said valve chamber for operating said valve, andthermostatic fluid pressure means containing a gas which does not changeits state at operating temperatures operatively connected to said fluidpressure means, said fluid pressure means including a thermostatic bulboperatively connected to the diaphragm means for regulating the loadingof said diaphragm means by the fluid pressure means, and means forvarying the volume of the fluid pressure means for adjusting the loadingof said diaphragm means by the fluid pressure means.

6. A'refrigerant expansion valve including a valve chamber having aninlet-and an outlet, a valve for controlling the flow of refrigerantthrough the valve chamber, a diaphragm means subject to refrigerantpressures within said valve chamber for operating said valve, andthermostatic fluid pressure means containing a gas which does not changeits state at operating temperatures operatively connected to said fluidpressure means, said fluid pressure means including a thermostatic bulboperatively connected to the diaphragm means for regulating the loadingof said diaphragm means by the fluid pressure means, and means forvarying the volume of said thermostatic bulb.

7. A refrigerant expansion valve including a valve chamber having aninlet and an outlet, a valve for controlling the flow of refrigerantthrough said valve chamber, and thermostatic fluid pressure meanscontaining a gas which does not change its state at operatingtemperatures for thermostatically regulating said valve, said fluidpressure means including means for vary- I ing the volume thereof foradjusting the fluid pressures therein.

8. Refrigerating apparatus including an evaparating means and means forcirculating refrigerant through the evaporating means, and thermostaticfluid pressure means containing a gas which does not change its state atoperating temperatures for controlling the circulation of refrigerantthrough the evaporating means, said fluid pressure means including meansfor vary- 4 ing the volume thereof for adjusting the fluid pressurestherein. 1

9. A refrigerant expansion valve including a valve chamber having aninlet and an outlet, a valve for controlling the flow of refrigerantthrough said valve chamber, means for controlling said valve includingmeans responsive to the pressure within said valve chamber andthermostatic fluid pressure means containing a gas which does not changeits state at operating temperatures for thermostatically regulating saidvalve, said fluid pressure means including means for varying thepressure therein to vary the control of the valve.

DONALD H. REEVES.

CERTIFICATE OF CORRECTION.

Patent No. 2,052,894. September 1, 1956 DONALD H. REEVES.

It is hereby certified that error appears in the printed specificationof the above. numbered patent requiring correction as follows: Page 5,first column, line 20-21, claim 5, and line 37-38, claim 6, for thewords "fluid pressure" read diaphragm; and that the said Letters Patentshould be read with these corrections therein that; the same may conformto the record of the case in. the Patent Office;

Signed and sealed this 20th day of October, A; 'D. 1956.

- Leslie Frazer (Seal) Acting Commissioner of Patents.

